You can't get the Quilter 803 to sound identical to Sisma.
- Like the Quilter 800, the 803 has the "heft and authority" that you have with tube head, and is often missing from class D amps (of course, Sisma has it too).
- The tube emulation on the Quilter 803 is realistic, much more so than what I've seen on other solid state amps.
- But they both have a different voicing, and I don't think it's possible to EQ the Quilter to sound excactly like Sisma. It's hard to explain, probably something special in the mids…? I can't say more.
That said, @badsneakers is not looking for an amp that sound like Sisma, he's looking for a all-in-one solution to Oracle+power amp. There are other good hybrid amps, especially the Mesa Bass 800D.
I'd be curious to try a hybrid amp that nobody is talking about: the GR Bass Groove. From the description and the very few demos available, I think I would like it.
I would never buy an amp if I don't like how it looks. Simply because there are enough great options available, I don't need to buy something I dislike. I know a lot of members find it ridiculous, but I don't care. Would you buy a car you find ugly?
I love the aesthetics of the Quilter 803, which I think has a nice "industrial" feel, and the brush metal enclosure lools much better in real life than on the photos — but I understand that others dislike it.
For Markbass it's different: the yellow color is so ugly that I don't understand how anyone can tolerate it, and I think there should be a low to punish Markbass for crime to good taste.
To be honnest, I bought a Markbass amp long ago, dispite the ugly color. It was a 801, because at that time there was no alternative for a super small amp that actually sound like a real bass amp. But I sold it as soon as I could, when I found the Phil Jones Double Four.